Scribing instrument



`lune 27, 1961 E. H. KOENIG SCRIBING INSTRUMENT vFiled Oct. 4, 1956 /IWL-Wl? B EUGENE H. KOENIG United States vPatent F Ierse y Filed Oct. 4, 1956, Ser. No. 613,855

2 Claims. (Cl. 33-27) This invention relates to a scribing instrument of the type used in map making. However, this type of instrument has many other uses and as is known to those skilled in the art can be used in any application where it is desired to make a negative drawing by scribing into an opaque coating provided on a transparent base material.

A scribed drawing can be used directly as a negatlve for the reproduction of the drawing on photosensitive materials by contact exposure. an improvement on the type of scribing instrument which is made up of a heavy body provided with three feet for contacting the surface to be scribed. A spindle carrying the scribing tool is secured to this body and the scribing tool is forced downward against the surface to be scribed by means of a compression spring provided within the spindle. Y

lOne object of the present invention is to provide a scribing instrument of the above type with means for drawing small circles of a predetermined radius by merely rotating a shaft carrying the scribing tool. g

.Another object of the present invention is to provide means on a scribing instrument of the above type which 'Ihe present invention is will permit the scn'bing instrument to be used for drawing l straight lines.

'Ihese and other objects of the invention and the means for their attainment will be more fully understood after reading the following description taken in conjunction with the accompanying drawing in which:

FIG. I is a view in plan of the new scribing instrument.

FIG. II is a view in elevation partly in section ofthe new scribing instrument; the sectional part being Vtaken along the horizontal center line of the scribing instrument as shown in FIG. I.

FIG. III is a view of the bottomvof the scribing instrument shown in FIGS. I and II with a portion of the magnier being broken away in order to save space.

FIG. IV is a view in enlarged sectional elevation of the spindle of the new scribing instrument takenral'ong-the line IV-IV of FIG. I and looking in the direction of the arrows. The tool holder carried at the lower end ofthe spindle is not in section. o A

Referring to the drawings, the body 2 of the scribing instrument Vis made up of a casting of substantial weight of a material such as brass or the like. For proper functioning of the circle scribingpmeans of the present invention, it is important that the weight of the body be substantially heavier than scribing instruments which have previously been used. 'Ihe body l2'is provided three feet v4 which are carried atthe lower-.endlof threescrews 6 threaded through the casting as-showri'in FIG-.IL Preferably the feet 4 consist of steel balls inserted into recesses provided in the bottom end o-f the screws 6 and the balls are held in the screws by spinning some of the metal of the screws over the balls. An anti-friction Washer such as the washer 7 which may be made of polytetrafluoroethylene may be provided in each of the recesses in the screws 6 above the balls. The body 2 is also provided with a vertical cylindrical hole through the extension 14 of the body to receive the spindle 8. As shown in FIG. IV, the spindle 8 includes a vertical tubular member 10 which is provided with a horizontal shoulder 12 which contacts the upper surface of the body 2. The portion of the vertical tubular member 10 -which extends below the shoulder 12 is provided with an outer cylindrical surface ice which lits the vertical cylindrical hole through the extension 14 of the body 2. A knurled set screw 16 showng in FIG. III is provided to secure the spindle 8 to the body .A 2.

A shaft 18 is mounted in the bore of the vertical tubular member 10 by means of two ball bearings 20 and `2 2; as shown in FIG. IV. The outer race of the upperball bearing 20 is mounted in a cap 24 which is free to slidep in the vertical direction within the upper enlarged bore, 26 of the vertical tubular member 10. .A compression spring 28 urges the cap 24 and thereby also the shaft 18 downwardly. Thus a tool 30 carried in the tool holder 32 will be forced against the surface of a scribe material by the pressure of the compression spring 28. The lower end of the shaft 18 is provided with `a conical taper 34` terminating in a threaded cylindrical portion of reduced: diameter. The lower end of the shaft 18 is also Ysplit from line 38 downward. The threaded portion tsaj matching thread in the vtool holder 32 which is providedY with a conical surface which engages the conical portion..l 34 of the shaft when the tool holder 32 is tightened on the shaft by means of the threads. The engagement of; the conical surface compresses the split end of the shaft,` 18 to hold the tool holder 32 firmly on the shaft. A pin: hole 40 is provided in the shaft 18 for use in holding the shaft by inserting a pin therein when the tool holderV 32 is tightened thereon. Y f

The tool holder 32 is removable byl merely turningit with respectto thershaft 18 -to disengage the threaded portion 36 from the tool holder 32. A conventional tool holder may then be attached to the shaftr18 byrmeansof the threadedportion at the end of the shaft and the. conical surface 34 or a tool may be inserted directly in the; vertical hole in the threaded portion 36A at the end of` the shaft 18 and held therein by a suitable chuck engaging the conial surface 34.

As shown in FIG. IV, the tool holder 32 includes la lxed yoke member 41 opening downwardly and a movable block member 42 held in the Aopening of the yoke` member 41 by two screws 43 and-45 which pass through` holes in each of the projections of the yoke member 41. and which are threaded into the block member 42.. The position of the movable block member42 in the horizontal direction can be adjusted by manipulating the screws 43 and 45. `A scale 47 is provided on the side of yoke member 41 and an index mark 49 is provided on-the side of theblock member 42. This scale 47 and index mark 49 indicate the horizontal position of the block member 42 and thereby the radius of the tool 30from the axis ofthe shaft 18. The tool 30 is held in a vertical hole in the block member 42 and is secured therein means of the knurled headed set screw 44. f The outer race of the bearing 22 is Jxed in the vertical tubular member 10. However, the shaft 18 is free to slide through the inner race of the bearing 22 in order that ythe shaft 18 will be responsive to thel action of the compression spring 28.` VThe upper end of the compression spring 28 is coniined by the cap 46 which is threaded on the vertical tubular member 10. The outside surface of the cap is knurled for ease in turning the cap in order t0 adjust the pressure applied to the tool by means of the compression spring 28.

In order to permit rotation of the shaft 18 so that the tool 30 will scribe a circle of radius determined by the adjustment of the block member 42 a shaft extension 49A passes through the cap 46 and the cap '24 and is secured to the shaft 18 by engaging threads as shown. A knurled wheel 51 is secured to the upper end of the shaft extension 49A by means of a screw 53. A knob 55 is fastened to the knurled wheel 51 by means of a screw 57. The shaft 18 may be turned by means of the wheel 51 or by using the knob 55 and wheel 51 as u crank means so that the tool 30 will inscribe small circles.

A block 59 which is provided with a lower friction surface as, for example, by cementingthereto a piece of rubber sheet 61 is carried below the body 2 by a second vertical shaft 63 passing through a hole provided near the center of the body 2. A button 65 is secured to the top end of the shaft 63 and a compression spring 66 engages the button 65 and a horizontal shoulder within the hole of the body 2 to lift the friction surface of the block 59 off the surface to be scribed. When it is desired to scribe circles with the scribing instrument, the friction surface 61 is brought into contact with the surface to be scribed by pushing downward on the button 65. This prevents the body 2 from slipping on the feet 4 when scribing the circle since the block 59 is keyed in a rectangular opening at the bottom of the body 2.

A portion of the underside of the body 2 is removed to make room for a straightedge 67 which is held to the body 2 by means of one ofthe screws 6 and an additional screw 69. The straightedge may be made of any material suitable for straightedges such as steel and the straightedge is provided at the outside edge along the line 71. By sliding the edge 71 along another straightedge the scribing tool will be caused to scribe a straight line. For this purpose, it may be desirable to carry the tool in a conventional tool holder.

A magnifier 56 in the form of a sector of a lens is attached to the vertical tubular member in order to permit close viewing of the tool 30. The magnifier 56V is attached by means of two metal strips 58 and 60 (shown in FIG. I) which are screwed against the radial surfaces of the lens 56 as shown and then bent parallel to each other. The metal strips 58 and 60 are provided with holes to receive the screw 62 which is shown in FIG. II. Another metal strip 64 is bent around the tubular member 10 and is also provided with holes to receive the screw 62. The magnifier 56 may be tilted about the screw 62 as an axis for the best viewing of the tool 30. The magnifier may also be pivoted around the vertical tubular shaft 10 for the same purpose. By tightening a nut provided on the screw 62 sufcient friction can be produced between the metal strips 58 and 60 and the metal strip 64 and between the metal strip 64 and the vertical tubular member 10 so that the magnifier 56 will hold its adjusted position.

Having thus described the invention what is claimed l. A scribing instrument comprising a relatively heavy body provided with three feet for engaging a surface to be scribed, a vertical tubular member carried by said body, a shaft mounted to slide and rotate in said vertical tubular member and projecting below said body, a tool holder carried on the lower end of said shaft including a xed yoke member opening downwardly and a movable block member held in the opening of said yoke member by two screws threaded into said block member and passing through holes in each of the projections of said yoke member so that the position of said movable block member can be adjusted by means of said screws, a scale provided on said tool holder for indicating the position of said movable block member with respect to the axis of said shaft, said movable member being provided with means for holding a tool so that the tool may be offset a predetermined amount from the axis of rotation of said shaft, a spring in said vertical tubular member forcing said shaft downward for urging the tool into a surface to be scribed and a handle provided on `the upper end of said shaft for rotating said shaft whereby a tool carried by said tool holder can be caused to scribe a small circle of predetermined radius.

2. A scribing instrument comprising a relatively heavy body provided with three feet for engaging a surface to b e scribed, a vertical tubular member carried by said body, a shaft mounted to slide and rotate in said vertical tubular member and projecting below said body, a tool holder carried on the lower end of said shaft including a xed yoke member opening downwardly and a movable block member held in the opening of said yoke member by two screws threaded into said block member and passing through holes in each of the projections of said yoke member so that the position of said movable block member can be adjusted by means of said screws, a scale provided on said tool holder for indicating the position of said movable block member with respect to the axis of said shaft, said movable member being provided with means for holding a tool so that the tool may be offset a predetermined amount from the axis of rotation of said shaft, a spring in said vertical tubular member forcing said shaft downward for urging the tool into a surface to be scribed, a block having a lower friction surface carried below said body by a second vertical shaft passing through said body, a spring urging said second vertical shaft upward to hold said friction surface off of a surface to be scribed, means on said second vertical shaft projecting above the top of said body so that said second vertical shaft can be pushed downward to cause the friction surface to engage a surface to be scribed and thereby prevent the scribing instrument from sliding on the surface to be scribed and a handle provided on the upper end of said rst shaft which rst shaft is mounted to slide and rotate in said vertical tubular member for rotating said first shaft whereby a tool carried by said tool holder can be caused to scribe a small circle of predetermined radius.

References Cited in the le of this patent UNITED STATES PATENTS 611,625 Goddard Oct. 4, 1898 813,095 Hottman Feb. 20, 1906 1,343,968 Hahn June 22, 1920 2,382,029 Scott Apr. 6, 1943 2,694,258 Miller et al Nov. 16, 1954 2,734,272 Brown Feb. 14, 1956 2,744,329 Way et al May 8, 1956 2,748,474 Brown June 5, 1956 .2,810,960 Johnson et al. Oct. 29, 1,957

FOREIGN PATENTS 38,858 Germany Sept. 1,5, 1886 97,703 Sweden Dec. 27, 1939 

